I have correctly added my UCF file to the Project Navigator project, but when I run the Back-Annotate Pin Locations process, the following error occurs:
"Started : "Back-Annotate Pin Locations".
ERROR: you must set the property 'Target UCF File Name'."
Project Navigator (ISE software 10.1 and later) allows a project to have multiple User Constraint Files (UCFs). In order for the Back-Annotate Pin Locations process to know which UCF to annotate the pin constraints to, the "Target UCF File Name" needs to be set. This property is located by right-clicking the Back-Annotate Pin Locations process and selecting Properties.